1. Field of the Invention
The present invention relates to an anti-vibration apparatus to be interposed between a vibration generating section and a vibration receiving section, and, more particularly, to an anti-vibration apparatus of the type which contains liquid and which absorbs vibrations by virtue of the resistance against flow of the liquid.
2. Description of the Prior Art
Known anti-vibration apparatuses to be employed in engine mountings, cabin mountings, or body mountings of vehicles include one which has a liquid chamber partly formed of an elastic body. The liquid chamber is generally divided by partition walls into a plurality of small liquid chambers, and the small liquid chambers communicate with each other through orifices.
When vibrations are generated, the liquid contained in one of the small liquid chambers moves toward the other small liquid chambers through the orifices, and the energy of the vibrations is absorbed by virtue of the resistance to the passage through the orifices of the liquid.
In such an anti-vibration apparatus, in order to cope with the vibrations of different frequencies which are generated in a vehicle, a plurality of orifices having different apertures must be provided in such a manner that they are opened and closed separately by a means such as valves.
An anti-vibration apparatus of a type which is capable of changing the velocity of the fluid contained therein in response to an load applied thereto, by applying an electric field thereto, (such as that disclosed in the specifications of Japanese Patent Laid-Open No. 104828/1985 and Japanese Patent Laid-Open No. 74930/1986) has also been known. However, the orifices in this apparatus are short, and sufficient damping is not guaranteed.